Light emitting device and method of forming the same
A light-emitting device includes a transparent substrate, a transparent adhesive layer on the transparent substrate, a first transparent conductive layer on the transparent adhesive layer, a multi-layer epitaxial structure and a first electrode on the transparent conductive layer, and a second electrode on the multi-layer epitaxial structure. The multi-layer epitaxial structure includes a light-emitting layer. The transparent substrate has a first surface facing the transparent adhesive layer and a second surface opposite to the first surface, wherein the area of the second surface is larger than that of the light-emitting layer, and the area ratio thereof is not less than 1.6.
1. A light-emitting device, comprising:
an epitaxial structure comprising an active layer;
a transparent substrate having a top surface being not less than 1.6 times an area of the active layer;
a first transparent layer, directly connected to the transparent substrate and comprising a widest width smaller than that of the transparent substrate and larger than that of the epitaxial structure;
a second transparent layer, made of oxygen and only one metallic element, arranged between the first transparent layer and the epitaxial structure; and
a first electrode arranged on the first transparent layer and the second transparent layer which are not covered by the active layer,
wherein the second transparent layer and the transparent substrate have outmost sidewalls which are not coplanar with each other.
2. The light-emitting device of claim 1 , wherein the transparent substrate comprises an inclined side surface.
3. The light-emitting device of claim 1 , wherein the transparent substrate has a bottom surface being not less than 1.6 times the area of the active layer.
4. The light-emitting device of claim 3 , wherein the top surface and the bottom surface have different widths.
5. The light-emitting device of claim 3 , wherein the top surface and the bottom surface substantially have the same width.
6. The light-emitting device of claim 1 , wherein the active layer is narrower than the second transparent layer.
7. The light-emitting device of claim 1 , wherein the epitaxial structure is devoid of a substrate which is used to form the epitaxial structure.
8. The light-emitting device of claim 1 , wherein the first electrode is directly connected to the second transparent layer.
9. The light-emitting device of claim 1 , wherein the transparent substrate is made of a non-semiconductor material.
10. The light-emitting device of claim 1 , wherein the second transparent layer comprises a metal oxide.
11. The light-emitting device of claim 1 , wherein the first transparent layer has a thickness is smaller than that of the second transparent layer.
12. The light-emitting device of claim 1 , wherein the first electrode is separated from the active layer.
13. The light-emitting device of claim 1 , further comprising a second electrode arranged on the epitaxial structure.
14. The light-emitting device of claim 1 , further comprising a reflective layer associated with the transparent substrate and has a width greater than the epitaxial structure.
15. The light-emitting device of claim 14 , wherein the reflective layer is a distributed Bragg reflector (DBR).
16. The light-emitting device of claim 1 , further comprising a reflective layer arranged under the active layer.
17. The light-emitting device of claim 1 , wherein the transparent substrate has a thickness between 50 to 200 microns.